In these days, nucleic acids (DNA=deoxyribonucleic acid, RNA=ribonucleic acid) are subject to various analyses and assays in the above-described technical field. In order to detect small amounts, the well-known polymerase chain reaction (PCR) can be used to replicate the target nucleic acid sequence to an amount which is detectable. The amplification of nucleic acids using the polymerase chain reaction has been extensively described in the patent literature, for instance, in U.S. Pat. Nos. 4,683,303, 4,683,195, 4,800,159 and 4,965,188. Generally, in the polymerase chain reaction, samples containing reaction mixtures of specific reagents and nucleic acids are repeatedly put through a sequence of amplification steps. Each sequence includes melting the double-stranded nucleic acids to obtain denaturated single polynucleotide strands, annealing short primers to the strands and extending those primers to synthesize new polynucleotide strands along the denaturated strands to make new copies of double-stranded nucleic acids. Due to the fact that reaction conditions strongly vary with temperatures, the samples are put through a series of temperature excursions in which predetermined temperatures are kept constant for specific time intervals (“thermo-cycling”). The temperature of the samples typically is raised to around 90° C. for melting the nucleic acids and lowered to a temperature in the range of from 40° C. to 70° C. for annealing and primer extension along the polynucleotide strands.
It is also known to detect the PCR reaction products during progress of the polymerase chain reaction (“real-time PCR”) to detect the presence or absence of a target nucleic acid sequence (or analyte) and/or to quantify the original amount of target nucleic acid which was present in the sample. In daily routine, commercially available instruments are being used for performing the PCR and detecting the reaction products obtained by means of fluorescence.